A demonstration of aldehyde-lactol tautomerism in gossypol by1H and13C NMR spectroscopy

1. The existence of a tautomeric equilibrium between the aldehyde and lactol forms gossypol has, for the first time, been demonstrated through NMR spectroscopy. In DMSO, gossypol exists primarily in the lactol form, and primarily in the aldehyde form in acids, bases, and inert solvents. 2. The method of preparation of the ethers of this compound determines the form of the product obtained.